Whatever you think, you don’t necessarily know your own mind

It is well established that people sometimes think they have beliefs that they don’t really have. For example, if offered a choice between several identical items, people tend to choose the one on the right. But when asked why they chose it, they confabulate a reason, saying they thought the item was a nicer colour or better quality. Similarly, if a person performs an action in response to an earlier (and now forgotten) hypnotic suggestion, they will confabulate a reason for performing it. What seems to be happening is that the subjects engage in unconscious self-interpretation. They don’t know the real explanation of their action (a bias towards the right, hypnotic suggestion), so they infer some plausible reason and ascribe it to themselves. They are not aware that they are interpreting, however, and make their reports as if they were directly aware of their reasons.

Many other studies support this explanation. For example, if people are instructed to nod their heads while listening to a tape (in order, they are told, to test the headphones), they express more agreement with what they hear than if they are asked to shake their heads. And if they are required to choose between two items they previously rated as equally desirable, they subsequently say that they prefer the one they had chosen. Again, it seems, they are unconsciously interpreting their own behaviour, taking their nodding to indicate agreement and their choice to reveal a preference.

Building on such evidence, Carruthers makes a powerful case for an interpretive view of self-knowledge, set out in his book The Opacity of Mind (2011). The case starts with the claim that humans (and other primates) have a dedicated mental subsystem for understanding other people’s minds, which swiftly and unconsciously generates beliefs about what others think and feel, based on observations of their behaviour. (Evidence for such a ‘mindreading’ system comes from a variety of sources, including the rapidity with which infants develop an understanding of people around them.) Carruthers argues that this same system is responsible for our knowledge of our own minds. Humans did not develop a second, inward-looking mindreading system (an inner sense); rather, they gained self-knowledge by directing the outward-looking system upon themselves. And because the system is outward-looking, it has access only to sensory inputs and must draw its conclusions from them alone. (Since it has direct access to sensory states, our knowledge of what we are experiencing is not interpretative.)

The reason we know our own thoughts better than those of others is simply that we have more sensory data to draw on.